The need for expansion joint structures between segments of bridge decking and between bridge decking and adjacent structures, as well as between adjacent sections of a structural body, such as a building, a roadway, or the like, are well known and have long been recognized. Accordingly, there have been many proposals for such structures.
All of the expansion joint structures are subject to several constraints. For example, such structures are subject to vehicular traffic, and thus must be sufficiently strong to withstand the loading associated with such traffic. Further, the joint structure must be designed to provide a smooth and quite ride thereover without skidding, and must be able to resist snow plow loading without moving. Still further, such joint structures are often subject to the corrosive action of sale and other snow-control materials, yet the structure must be easily accessible for inspection, maintenance, replacement and modification. Still further, such expansion joint structures should be easily and inexpensively stored, transported, and installed in a wide variety of applications.
These various requirements have led to several different design proposals. For example, some designs have included interdigitating metal fingers or overlapping metal tongues. While somewhat successful, such metal expansion joint structures are unduly subject to attack by the corrosive salts and other snow control materials thereby creating maintenance, binding and other failure-producing problems, especially in climates having a great deal of snow fall.
Even protecting such metal joints by placing a protective mat thereover has not been entirely successful.
Therefore, further designs have been proposed which have included non-metal joint structures. Elastomeric materials have been used as the primary non-metal material.
However, such joint structures have not been entirely successful either since non-metal structures have a tendency to become brittle, and are not as resistant to wear and tear as are the metal structures, thereby increasing the maintenance costs associated therewith. In particular, such non-metal joint structure are susceptible to being damaged by snow plows.
Accordingly, there is a need for an expansion joint structure that is as reliable as metal, yet is designed in a manner that overcomes the above-mentioned problems that have been associated with heretofore proposed metal joint structures.